When, in Act 1, Scene 3, Cassius gives Cinna some letters, he tells him
...look you lay it in the praetor's chair,
Where Brutus may but find it; and throw this
In at his window.
Brutus is one of the praetors, then - though in traditional Roman history there were sixteen praetors. The Soothsayer, later on, in 2.4, says
Here the street is narrow:
The throng that follows Caesar at the heels,
Of senators, of praetors, common suitors,
Will crowd a feeble man almost to death:
I'll get me to a place more void, and there
Speak to great Caesar as he comes along.
There you have it. There are lots of praetors, in Shakespeare's mind, at least. But Brutus is one of them.